LinuxQuestions.org - DNAT issue with iptables

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DNAT issue with iptables

Hi Guys

Im very much a n00b when it come to iptables etc

heres my setup

2 nics , WAN & LAN

eth0 = LAN =192.168.10.10
eth1 = WAN = 123.123.123.123

I am trying to DNAT incoming traffic on 123.123.123.123:9180 to 192.168.10.10:80

rule im using

-A PREROUTING -i eth1 -p tcp -m tcp --dport 9180 -j DNAT --to-destination 192.168.10.10:80

where the

--dport 9180 is that of eth1

is this correct or what am i missing , for the life of me i cannot get this to work ?

does my http server need to use my router as the Default gateway ?

any help will be greatly appreciated
im really just trying to get my head around iptables etc

You have to add rule to firewall to allow the nated packets to be allowed on FORWARD chain

Code:

iptables -A FORWARD -p tcp -i eth1 -o eth0 -d 192.168.10.10 --dport 80 --sport 1024:65535 -m state –state NEW -j ACCEPT

iptables -A FORWARD -t filter -o eth1 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -t filter -i eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT

Is the ip_forward allowed ?

Code:

cat /proc/sys/net/ipv4/ip_forward

Should return 1